This invention relates to paraffin scrapers. In one of its aspects this invention relates to field installed paraffin scrapers. In still another aspect of this invention it relates to stamp molded prepregs of inorganic reinforcing material surrounded by a poly(phenylene sulfide) matrix.
The use of rod guides and paraffin scrapers is well known in the art. Rod guides, generally made of polymeric material, are fitted around the sucker rods in pumping oil wells to maintain the spacing between the sucker rod and the tube thereby minimizing wear of the tube or rod during the reciprocating action of the rod during the pumping operation. The rod guides are spaced along the sucker rods to provide the protective action.
A paraffin scraper is a rod guide of specific conformation which provides a scraping action to remove paraffin that has solidified around the sucker rod by reduction of temperature as the paraffin is moved up the well toward the surface.
In U.S. Pat. No. 3,399,730 rod guides and paraffin scrapers are set forth which are produced as a pair of substantially identical half-sections which can be placed on the sucker rods in the field and wedged around the rod in a locked position so that the protuberances on the rods are secured in a manner that precludes slippage along the rod. This patent states that a rod guide or paraffin scraper should preferably be constructed from a suitable plastic material which is corrosion resistant, sheds paraffin, and has insulating properties for protection of the rod from electrolytic action. The reference illustrates the rod guide or paraffin scraper only as being made from nylon. U.S. Pat. No. 3,399,730 is incorporated here by reference to show the configuration of a rod guide or paraffin scraper which is essentially the conformation of the produced object useful in the present invention.
It is also known that the properties poly(phenylene sulfide) as far as corrosion resistance, being able to shed paraffin, and having insulating properties for protection of the rod from electrolytic action should provide a material of construction that is quite suitable for the end use set out in this invention. Indeed, rods have been produced that have rod guides or scrapers molded onto the rod during the production process with the rod guide made from poly(phenylene sulfide) with the product achieving excellent results in its end use. There has, however, been a drawback in that, because of the ductility of the material, poly(phenylene sulfide) rod guides such as those set out in U.S. Pat. No. 3,399,730 which can be applied in the field could not be produced from poly(phenylene sulfide). Applicants have now solved the problem of providing a product having the useful characteristics of poly(phenylene sulfide) in the end product but also having suitable ductility to be made into half-sections that can be wedged around a rod in locked position in the field.
It is therefore an object of this invention to provide a rod guide or paraffin scraper of reinforced poly(phenylene sulfide) made as half-sections adapted to be wedged around a rod in the field.
Other aspects, objects and the various advantages of this invention will become apparent upon reading the specification and the appended claims.